An established method of configuring elastomeric seals, typical of O-ring type seals, to seal the gap between assembled first and second close-fitting solid components, separated by an extrusion gap, is to provide a resilient, compliant, and substantially incompressible seal element (mechanical properties characteristic of elastomers) in a generally rectangular seal groove of a controlled depth (defining the groove bottom surface) and width (defining the groove sidewall surfaces) placed in the first component, referred to herein as the seal carrier, adjacent to a seal surface provided in the second component, referred to herein as the workpiece. The unconstrained seal element depth is selected to exceed the sum of the groove depth and gap between the seal carrier and the seal surface of the workpiece, so that interference is created between the seal element and the groove bottom and workpiece seal surfaces of the assembled components. This interference tends to deform the compliant elastomer by compression in a direction normal to the seal surface and, due to its substantially incompressible bulk properties, elongation in the transverse direction. To accommodate the elongation, the seal groove width typically slightly exceeds the seal element's deformed width to volumetrically accommodate this deformation. This is typically desirable to promote pressure activation and avoid pressure entrapment in the cavities between the sidewall and the seal element.
Configured thus, the seal element is forced into contact with the workpiece surface and the groove bottom where, as is known in the art, the initiation of the seal function is dependent on arranging the design parameters of geometry, surface roughness, elastomer compliance, and amount of interference to ensure that the initial contact stress distribution is sufficient to result in conforming contact both between the seal element and the workpiece surface and between the seal element and the seal groove bottom. However, the effectiveness of this type of seal in some applications is limited, especially where surface roughness of the workpiece is high and cannot be readily controlled, and where the extrusion gap tolerances are loose. In such applications, it can be difficult or impossible to arrange the available design parameters to provide the amount of interference required to achieve a reliable seal, within the allowable deformation limits of the available elastomeric materials with respect to material properties, and within seal load constraints.
Also, the established method of installing an elastomeric seal is to stretch the seal element over the seal carrier into the fixed-geometry groove. This method of installation becomes increasingly difficult as the seal element thickness become large relative to the seal length.
The present invention addresses the foregoing problems.